Two-duct drainage fixtures are constituted by a fine silicone tube designed to be intubed in the tear ducts in order to remedy certain dysfunctions such as stenoses that block said duct. The ducts communicate with the eye via meatuses located close to the nose in the top and bottom eyelids, and their function is to remove tear fluid via the nose.
It is known that in the event of these ducts being diseased, they can be intubed by means of a flexible filament or tube that unblocks the stenoses and reestablishes the flow of tear fluid. The problem solved by the invention is that of intubing tear ducts. At present, the silicone tube to be inserted in the ducts is terminated at each of its ends by a flexible metal mandrel that serves as a guide for following a twisting path. The drawback of that method of putting the tube into place is that it usually leads to bleeding, particularly when bringing the mandrels out into the nasal cavity, and in any event it is traumatic. Such a method is described in U.S. Pat. No. 4,380,239-Crawford et at.
The problem can be remedied using the Busse technique in association with a Ju/ nemann probe. The Busse technique essentially consists in passing a fine filament along the ducts and then in using the filament to pull the silicone tube which is of greater diameter.
A Ju/ nemann probe is in the form of a hollow cannula having fins for grasping purposes at its top end and a lateral hole at its bottom end, its leading tip being closed. The leading end of the probe is initially cathetered in the meatus in a position that is slightly inclined relative to the horizontal so as to penetrate into the horizontal portion of the duct, after which it is caused to rotate through substantially 90.degree. and a fine guide filament, e.g. of prolene, is pushed inside the probe and then inside the nasal cavity from which it can be retrieved by means of a hook or tweezers. The Ju/ nemann probe is then slid from the other end of the filament from which it escapes. This operation is repeated in each of the two ducts. After which each of the guide filaments is united to the end of the probe proper.
That technique has the advantage of avoiding bleeding and of being non-traumatic. However, compared with the two-duct probes mentioned above it requires more time and it is considerably more complex. The length of time required is due in particular to the fact that the surgeon must make the connection between the prolene filament and the silicone tube after extracting the probe.
The surgeon therefore needs to perform the following operations in succession:
a) inserting the cannula in a tear duct; PA1 b) pushing the guide filament into the cannula; PA1 c) pulling the guide filament from inside the nasal cavity; PA1 d) extracting the cannula from the tear duct and from the filament by making it slide upwards along the guide filament; PA1 e) connecting the guide filament to the silicone tube; PA1 f) causing the assembly comprising the guide filament and the silicone tube to move along the tear duct by pulling from below and pushing from above in small successive movements in order to avoid disconnecting the filament from the tube; and PA1 g) once the silicone tube appears in the nasal cavity, separating the filament from the tube and pulling thereon. PA1 providing each of the ends of the silicone tube with a guide filament of diameter smaller than the inside diameter of the hollow cylindrical body; PA1 providing a longitudinal slot inside the hollow cylindrical body and extending from the opening to the back end of the body; PA1 forming a narrow zone in the guide filament, the diameter of the narrow zone being slightly less than the width of the slot; PA1 inserting the cannula in a meatus; PA1 sliding the guide filament along the duct until it becomes apparent inside the nose; and PA1 causing the cannula to pass over the narrowed portion so as to disengage the guide filament.
After which the same operation needs to be performed in the other meatus.
The operation which is the most lengthy and the most difficult is step f). It is not possible for the surgeon to fix the guide filament to the silicone tube in advance since the cannula must be removed from the guide filament before the connection can be made.